The long-range objective of this research is to establish biomechanical, acoustic, and aerodynamic correlates of functional voice disorders that are implicated by the presence of the ventricular or false vocal folds (FVF). This goal, by necessity, must include the development and use of effective models of phonation, and quantification of the biomechanical, aerodynamic, and acoustic factors that control laryngeal function and voice quality. The objective of this application is to establish a firm understanding of the biomechanics, aerodynamics, and acoustics of false vocal fold oscillation. This objective will be met through a combination of experimental and computational methods. There are four specific aims in this project. These aims are: 1) To establish the detrimental effects of irregular FVF oscillations, 2) To identify the biomechanical and histological characteristics of FVF tissue, 3) To identify the aerodynamic and acoustic effects associated with FVF positioning, and 4) To quantify the biomechanical effects of the FVF on laryngeal oscillations. This proposal has strong clinical relevance as it addresses some of the major concerns in voice disorders such as ventricular disphonia. The successful completion of this project will enhance our understanding of the form and function of the ventricular vocal folds, both with respect to their influence in normal sound production and their contribution to altered or disordered voice. Detailed and systematic study of FVF anatomy, biomechanics, and neuromuscular control can be expected to provide important insights into the mechanism of sound production and its control, and improvements in our approaches to treating the pathological voice. In this proposal we intend to answer research questions regarding: vibratory characteristics (Fo range, amplitude of motion, symmetry of motion, modes), acoustic characteristics (dependence on adduction, lengthening, A-P compression), aerodynamics (pressure, flow, flow resistance, PTP), and tissue characteristics (elastic modulus, viscosity, muscle architecture). PUBLIC HEALTH RELEVANCE: This project investigates the biomechanics of the ventricular vocal folds and their functional behavior that associated with some voice disorders. It is an experimental and computational project that measures ventricular fold tissue structure and biomechanical properties and quantifies airflow and sound generation from normal and abnormal ventricular fold oscillations.